How to hide first 3 childs of UL using CSS

I have the following structure:

<ul id="test">
    <li class="myclass">Item1</li>
    <li class="myclass">Item2</li>
    <li class="myclass">Item3</li>
    <li class="myclass">Item4</li>
    <li class="myclass">Item5</li>
</ul>

I want to hide the first three items. I wrote the following code but it only hides the first child and not the next two.

#test li:first-child
{
    display:none;
}

How do I hide the other two also?